Switch construction

ABSTRACT

Disconnecting switch means for high-tension electrical power installations having a switch blade pivoted for movement by crank means about an arc and rotatable about its own axis into and out of pressure engagement with a fixed remotely spaced contact, and characterized by cam means for increasing the load-lifting ability when the switch is opened and the arm extends horizontally to transfer torque from the crank means to the switch blade to provide increased load-lifting ability.

United States Patent Inventor Roy T. Swanson North Riverside, Ill.

Appl. No. 879,408

Filed Nov. 24, 1969 Patented Nov. 9, 1971 Assignee H. K. Porter Company, Inc.

Chicago, Ill.

SWITCH CONSTRUCTION 12 Claims, 4 Drawing Figs.

US. Cl

Int. Cl..

Field of Search H0lh 31/00 [56] References Cited UNITED STATES PATENTS 3,038,052 6/1962 Froland 200/48 R&P

Primary ExaminerHerman J. Hohauser Attorney-Gary, Parker, .Iuettner, Pigott & Cullinan ABSTRACT: Diseonnecting switch means for high-tension electrical power installations having a switch blade pivoted for movement by crank means about an arc and rotatable about its own axis into and out of pressure engagement with a fixed remotely spaced contact, and characterized by cam means for increasing the load-lifting ability when the switch is opened and the arm extends horizontally to transfer torque from the crank means to the switch blade to provide increased load-lifting ability.

SWITCH CONSTRUCTION The invention relates to an improvement in disconnecting switches, particularly air break switches of the type having a switch blade movable in an-arc and rotatable about its own axis as shown in U.S. Pat. Nos. 2,527,924, 3,174,004 and 3,240,887.

In general, this type of switch comprises a base'member which can be mounted vertically or horizontally or in an inverted position, and mounting thereon a pair of spaced fixed insulators and an intennediately disposed rotatable insulator. One of the fixed insulators is disposed on the base remotely from and the other fixed insulator is disposed adjacent to the rotatable insulator, the fixed insulators carrying stationary contacts and terminal pads. The switch blade is pivotally supported on a horizontal axis from the fixed insulator disposed adjacent to the rotatable insulator and is connected to crank means on the rotatable insulator operable to rotate the switch blade about its longitudinal axis into and out of pressure engagement with the stationary contacts and to swing the blade about the horizontal pivot axis toward and away from the stationary contacts. Switches of the foregoing type are employed in open and exposed positions and at times under icing conditrons.

The present invention is concerned with the problem and the solution therefor when such switch is mounted vertically, i.e., with the switch blade adapted to extend vertically upward in closed position and horizontally outward in open position.

It is the object of the invention to provide cam means to increase the load-lifting ability of the switch means and to transfer torque from the crankshaft to the switch blade so that stress will be reduced, occurrence of failure diminished and an increased load-lifting ability provided from the horizontal blade-open position to the upwardly extending blade-closed position.

The objects and advantages of the present invention will be further explained in connection with the following specification and accompanying drawings wherein,

FIG. 1- is a side elevational view of the switch mechanism of the present invention with the blade in closed position.

FIG. 2 is a similar view with the switch blade horizontally disposed in open position.

FIG. 3 is a fragmentary side elevational view of the characterizing cam means for assisting in torque transfer of the actuating crank to the switch blade of the mechanism of the present invention.

FIG. 4 is a fragmentary bottom plan view of the characterizing torque assist means shown in FIG. 3.

Referring to the drawings, particularly FIGS. 1 and 2, the reference numeral indicates a channel iron base that is mounted vertically and in which position the present invention is particularly effective although as previously indicated the base can be mounted horizontal or in inverted position. Accordingly, the words horizontal and vertical as are used in the specification and claims with respect to axes of certain elements of the switch are to be considered to express certain relative positions of the axes with respect to each other since while the words accurately identify the axes which are illustrated in the drawings, the vertical and horizontal position might change if the switch of this invention were mounted other than in the vertical position shown.

The base carries insulators l1, l2 and 13 which are of conventional construction and, as shown, may be of the pin type. The insulators 11 and 13 at the ends of the base 10 are stationary. The intermediate insulator 12 is rotatable. For this purpose, a bearing 16 is mounted on the base 10 and as will appear hereinafter constitutes the sole bearing support for the insulator 12. Shank 17 projects below the base 10 and is arranged to receive suitable means for rotating insulator 12.

The insulator 11 is spaced remotely from the rotatable insulator 12 and at its outer end carries a terminal bracket 18 which may be a bronze, copper or aluminum casting and has a terminal pad 19 formed integrally therewith to which a terminal connector may be secured. Mounted on the terminal bracket 18 is a generally U-shaped stationary contact assembly 21 comprising one or more pairs of opposed fingers or arms secured to the base member and providing small area, high-pressure contact surfaces. Reinforcing springs are preferably provided to urge the arms of the contact assembly 21 toward each other to provide the required contact pressure against the terminal flat or beaver tail portion 32 at the forward end of switch blade 31 when the portion 32 is disposed transversely between the opposed pairs of arms.

It will be understood that the blade 31 is rotatable on its longitudinal axis so that the beaver tail end portion 32 can be disposed parallel to the contact members for ease in insertion between or withdrawal from the contact, and can be disposed transversely of the contact for high-pressure engagement therein.

The insulator 13 is disposed adjacent to the rotatable insulator l2 and carries a frame 25 terminating at one end in a pad or connector terminal 26 and at the other end in bifurcated arm portions 27, 27. The latter mount pivot pins or bolts 45 which engage arms 28, 29 of a tubular blade guide or hinge 44 to pivotally mount the guide on the frame on a horizontal pivot axis.

The switch blade 31 is carried by and secured at or adjacent its rearward end portion by a tubular blade carriage 40 which includes an arm or shaft 46 inclined thereto at an angle of about 45. The carriage is rotatably mounted within the hinge or guide 44 and the arm 46 extends therefrom toward the center insulator 12.

The free end of the arm 46 is rotatably mounted in a complemental bearing portion 48 of a crank pin 49 which is secured to the outer end of the rotatable insulator 12.

When the insulator 12 is rotated from the position shown in FIG. 1, the switch blade 31 will be rotated about its longitudinal axis to relieve the pressure between it and the high-pressure contact 21. Simultaneously, the rotation of the insulator 12 and the crank pin 49 causes the switch blade 31 to swing about the horizontal pivot axis defined by the bolts 45. When the movement of the insulator 12 has been completed, the switch blade 31 is moved to a horizontal full-open position and rotated about its longitudinal axis as shown in FIG. 2.

The blade hinge or guide 44 permits the switch blade 31 to rotate about its longitudinal axis, and is rockably mounted by the arms 28 and 29 on the arms 27, 27 of the frame 25 for movement about the horizontal axis of the bolts 45. Thus, the blade hinge guides the switch blade 31 in an arcuate movement from the vertical switch-closed position of FIG. 1 to the horizontal switch-open position of FIG. 2 and vice versa. Since the blade carriage 40 is fastened to the switch blade 31 and its arm 46 is rotatably mounted in the bearing portion 48 of the crank pin 49, rotation of the insulator 12 about its axis causes the crank pin 49, which is secured thereto, to initially cause the switch blade 31 to rotate about its longitudinal axis and thereafter principally about the horizontal axis to the bolts 45.

When the insulator 12 is rotated in a reverse direction, the switch blade 31 is swung to the switch-closed position. At the same time, the switch blade 31 is rotated about its longitudinal axis, the final rotation about this axis taking place as it approaches the vertical position so that the final movement thereof into high-pressure engagement with the contact 21 takes place while there is only a small amount of arcuate movement. This permits the necessary torque to be transmitted to the switch blade 31 rotating it into switch-closed position with the contact 21 under relatively high pressure.

In the blade opening cycle, the first approximately 22 of rotation of the insulator 12 causes the blade to rotate about its own axis to relieve the contact pressure and clear the contacts 21. The next approximately 23 of insulator rotation moves the blade arcuately about 15, thus providing a sizeable mechanical advantage in the vicinity of switch-closed position. For the balance of the insulator rotation, the blade pivots or moves arcuately at a rate, in degrees, exceeding the insulator rotation in degrees. The reverse sequence occurs when the switch is to be closed.

This sequence of operations provides for excellent blade control, and especially provides great mechanical advantage over arcuate movement of the blade adjacent the contact, and great mechanical advantage in blade rotation into and out of the contact, to insure proper operation of the switch even under such ambient conditions as severe icing. However, these advantages are attained by a diminution of blade control and mechanical advantage in the vicinity of switch-open position.

The latter factor is generally of little or no concern when the switch is mounted in upright horizontal position, nor is it of much concern in smaller switches; However, with the advent of the higher voltages prevalent today, it has recently been proposed to install larger switches than heretofore conventional in the vertical position shown in the drawings. In this environment, a long switch blade extends horizontally outward in switch-open position and is subject to severe icing, such that the load required to be raised is no longer within the load-lifting ability, or mechanical advantage in the switch-open position, of the conventional operating mechanism above described.

The present invention concerns itself with means of increasing the load-lifting ability of the switch, specifically, by provision of a correctly contoured radial cam 50 on the periphery of the bearing portion 48 of crank pin 49 and a cooperating cam follower 51 on the arm 28 of the blade guide or hinge 44; the function of the cam 50 and cam follower 51 being to transfer torque from the crank 49 to the blade 31 in the vicinity of switch-open position upon closing movement of the switch in such manner as to cause arcuate upward movement of the blade at a substantial increased efficiency. Inasmuch as the inherent mechanical advantage of the switch operating mechanism is deficient only in the vicinity of the switch-open position, the supplemental torque transmission function of the cam 50 and cam follower 51 is required only until the switch blade has reached approximately its 45 position.

For the stated purpose, the cam follower 51 is preferably a wheel or rotary bearing journaled at 52 on an angular shaft 53 extending outwardly from a rearward extension of the arm 28. The disposition of the cam 50 and its shape are such that the lowest point on the cam initially contacts the follower 51 when the blade 31 is in its fully opened horizontal position as shown in FlG. 2. As the insulator 12 and its associated crank pin 49 are rotated (so as to move the blade 31 arcuately upward toward the closed position shown in FIG. 1) the contour of the cam 50 increases in a radial direction so as to bear on the cam follower 51 and to force the rearward extension of arm 28 downwardly until approximately the time the blade reaches the 45 point in its upward travel, whereupon the conventional operating mechanism takes over and the cam follower 51 separates from the cam. To obtain excellent camming action without side-slip and unnecessary friction between the cam lll'ld the follower, the cam is preferably disposed at an angle of approximately 70-75 to the axis of the bearing portion 48, and the shaft 53 is preferably disposed at an inclination of approximately 60-65 to the arm 28. The contour of the cam is designed to match the blade movement characteristics of the remainder of the operating mechanism, and to provide gradual or smooth transfer of the load at approximately the 45 blade position.

While the main purpose of the cam and follower is to provide efficient load-lifting torque transfer during blade raising or closing movement, it also serves to provide greater blade control, especially controlled stopping of the blade in horizontal full-open position, during blade lowering or opening movement.

l claim:

1. in an electrical switch having swingable switch blade means, a frame, hinge means on the frame supporting the blade means for swinging movement between switch-open and switch-closed positions, an operating arm projecting from said blade means, and crank means rotatable about an axis which parallels the blade means when the blade is in switch-open position and is normal to the blade means when the blade is in switch-closed position, said crank means including means engaging said arm for moving the blade means between said positions, the improvement comprising a cam on said crank means and a cam follower on said hinge means mounted for engagement with one another at and in the vicinity of the switch-open position, said cam having a cam surface rising toward said follower in the direction of switch-closing movement of the crank means for transferring torque from the crank means to the hinge means upon switch-closing movement of the crank means.

2. [n the switch of claim 1, said cam surface being of an extent to engage said follower from switch-open position throughout approximately one-half of the swinging movement of the blade means toward switch-closed position.

3. In an electrical switch having rotatable and swingable switch blade means, a frame, hinge means on the frame supporting the blade means for rotary and swinging movement between an outwardly extending horizontal switch-open position and an upwardly extending vertical switch-closed position, an operating arm extending angularly from the blade means, and crank means rotatable about an axis which parallels the blade means when the blade is in switch-open position and is normal to the blade means when the blade is in switchclosed position, said crank means including bearing means extending angularly from said axis at an angle complementary to said arm and rotatably engaging said arm for rotating the blade means and for simultaneously swinging the blade means between said positions, the improvement comprising a cam on said crank means and a cam follower on said hinge means mounted for engagement with one another through an arc of blade movement at and in the vicinity of the horizontal switchopen position of the blade means, said cam having a cam surface rising toward said follower in the direction of and throughout a part of the switch-closing movement of the crank means for transferring torque from the crank means to the hinge means upon switch-closing movement of the crank means for assisting in lifting said blade means toward switchclosed position.

4. In the switch of claim 3, said cam surface being of an extent to engage said follower from switch-open position throughout approximately one-half of the swinging movement of the blade means toward switch-closed position.

5. in the switch of claim 3, said cam surface being inclined to the axis of said crank means and said follower being inclined to the axis of said hinge means for eliminating side slip between the cam and follower.

6. ln the switch of claim 5, said follower comprising a wheel.

7. In an electrical switch comprising a vertically disposed supporting base, a spaced pair of fixed terminals mounted on and extending horizontally from said base, a frame on the outer end of the lower one of said terminals, a blade hinge pivotally mounted on said frame, a switch blade rotatably mounted adjacent one end on said hinge, said blade being adapted to be swung arcuately in a vertical plane into and out of contact with the upper one of said fixed terminals and to be rotated about its longitudinal axis into and out of engagement with pressure contact means carried by said upper terminal, an operating arm extending from said one end of said blade toward said base at an acute angle to the blade axis, an operating shaft extending horizontally from said base toward said arm adjacent said lower terminal, a crank on the outer end of said shaft including a bearing portion complemental to and extending angularly toward and receiving said arm, said bearing portion rotatably engaging said arm for causing rotary and swinging movement of said blade upon rotation of said shaft to move said blade between a horizontal switch-open position and a vertical switch-closed position, the improvement comprising a cam extending essentially radially downward from the bearing portion of said crank in the switch-open position, a rearward extension on said hinge extending beneath said cam in switch-open position, and a cam follower on said extension for cooperation with said cam, said cam engaging said follower in the switch-open position and being of progressively greater radial extent in the direction of switch-closing movement of said crank for forcing said follower and said extension downwardly and effecting torque transfer from the crank to the blade in the initial stages of moving the blade upwardly toward switch-closed position.

8. In the switch of claim 7, said cam extending essentially circumferentially around said bearing portion to an extent to engage said follower from the horizontal switch-open position of the blade to a position substantially 45 upwardly therefrom.

9. In the switch of claim 7, said cam follower comprising a wheel carried by said hinge extension.

10. ln the switch of claim 9, said cam and said cam follower being dispose at complementary inclinations to said crank and said extension to mitigate friction therebetween.

ll. In an electrical switch having a swingable blade, a frame, hinge means on the frame supporting the blade for swinging movement between switch-open and switch-closed positions, an operating arm projecting from said blade, and crank means rotatable about an axis which parallels the blade means when the blade is in switch-open position and is normal to the blade when the blade is in switch-closed position, said crank means engaging said arm for moving the blade between said positions, the improvement comprising a cam on one of said means and a cam follower on the other of said means mounted for engagement with one another at and in the vicinity of the switch-open position, said cam having a cam surface rising toward said follower in the direction of switch-closing movement of the crank means for transferring torque from the crank means to the hinge means upon switch-closing movement of the crank means.

12. ln the switch of claim 1, said follower comprising a wheel. 

1. In an electrical switch having swingable switch blade means, a frame, hinge means on the frame supporting the blade means for swinging movement between switch-open and switch-closed positions, an operating arm projecting from said blade means, and crank means rotatable about an axis which parallels the blade means when the blade is in switch-open position and is normal to the blade means when the blade is in switch-closed position, said crank means including means engaging said arm for moving the blade means between said positions, the improvement comprising a cam on said crank means and a cam follower on said hinge means mounted for engagement with one another at and in the vicinity of the switch-open position, said cam having a cam surface rising toward said follower in the direction of switch-closing movement of the crank means for transferring torque from the crank means to the hinge means upon switch-closing movement of the crank means.
 2. In the switch of claim 1, said cam surface being of an extent to engage said follower from switch-open position throughout approximately one-half of the swinging movement of the blade means toward switch-closed position.
 3. In an electrical switch having rotatable and swingable switch blade means, a frame, hinge means on the frame supporting the blade means for rotary and swinging movement between an outwardly extending horizontal switch-open position and an upwardly extending vertical switch-closed position, an operating arm extending angularly from the blade means, and crank means rotatable about an axis which parallels the blade means when the blade is in switch-open position and is normal to the blade means when the blade is in switch-closed position, said crank means including bearing means extending angularly from said axis at an angle complementary to said arm and rotatably engaging said arm for rotating the blade means and for simultaneously swinging the blade means between said positions, the improvement comprising a cam on said crank means and a cam follower on said hinge means mounted for engagement with one another through an arc of blade movement at and in the vicinity of the horizontal switch-open position of the blade means, said cam having a cam surface rising toward said follower in the direction of and throughout a part of the switch-closing movement of the crank means for transferring torque from the crank means to the hinge means upon switch-closing movement of the crank means for assisting in lifting said blade means toward switch-closed position.
 4. In the switch of claim 3, said cam surface being of an extent to engage said follower from switch-open position throughout approximately one-half of the swinging movement of the blade means toward switch-closed position.
 5. In the switch of claim 3, said cam surfAce being inclined to the axis of said crank means and said follower being inclined to the axis of said hinge means for eliminating side slip between the cam and follower.
 6. In the switch of claim 5, said follower comprising a wheel.
 7. In an electrical switch comprising a vertically disposed supporting base, a spaced pair of fixed terminals mounted on and extending horizontally from said base, a frame on the outer end of the lower one of said terminals, a blade hinge pivotally mounted on said frame, a switch blade rotatably mounted adjacent one end on said hinge, said blade being adapted to be swung arcuately in a vertical plane into and out of contact with the upper one of said fixed terminals and to be rotated about its longitudinal axis into and out of engagement with pressure contact means carried by said upper terminal, an operating arm extending from said one end of said blade toward said base at an acute angle to the blade axis, an operating shaft extending horizontally from said base toward said arm adjacent said lower terminal, a crank on the outer end of said shaft including a bearing portion complemental to and extending angularly toward and receiving said arm, said bearing portion rotatably engaging said arm for causing rotary and swinging movement of said blade upon rotation of said shaft to move said blade between a horizontal switch-open position and a vertical switch-closed position, the improvement comprising a cam extending essentially radially downward from the bearing portion of said crank in the switch-open position, a rearward extension on said hinge extending beneath said cam in switch-open position, and a cam follower on said extension for cooperation with said cam, said cam engaging said follower in the switch-open position and being of progressively greater radial extent in the direction of switch-closing movement of said crank for forcing said follower and said extension downwardly and effecting torque transfer from the crank to the blade in the initial stages of moving the blade upwardly toward switch-closed position.
 8. In the switch of claim 7, said cam extending essentially circumferentially around said bearing portion to an extent to engage said follower from the horizontal switch-open position of the blade to a position substantially 45* upwardly therefrom.
 9. In the switch of claim 7, said cam follower comprising a wheel carried by said hinge extension.
 10. In the switch of claim 9, said cam and said cam follower being disposed at complementary inclinations to said crank and said extension to mitigate friction therebetween.
 11. In an electrical switch having a swingable blade, a frame, hinge means on the frame supporting the blade for swinging movement between switch-open and switch-closed positions, an operating arm projecting from said blade, and crank means rotatable about an axis which parallels the blade means when the blade is in switch-open position and is normal to the blade when the blade is in switch-closed position, said crank means engaging said arm for moving the blade between said positions, the improvement comprising a cam on one of said means and a cam follower on the other of said means mounted for engagement with one another at and in the vicinity of the switch-open position, said cam having a cam surface rising toward said follower in the direction of switch-closing movement of the crank means for transferring torque from the crank means to the hinge means upon switch-closing movement of the crank means.
 12. In the switch of claim 1, said follower comprising a wheel. 